【摘要】 应用电化学噪声（ｅｌｅｃｔｒｏｃｈｅｍｉｃａｌ　ｎｏｉｓｅ）技术对航空铝合金结构材料 ＬＣ４；ＬＹ１２ 及纯铝在质量分数为 ２．０％的ＮａＣｌ溶液中的腐蚀过程进行了研究．发现不同材料在发生点蚀时其电化学噪声的时域谱波形特征各不相同，电化学噪声的频域谱ＳＰＤ（ｓｐｅｃｔｒａ　ｐｏｗｅｒ　ｄｅｎｓｉｔｙ）曲线的三个特征参数：白噪声水平Ｗ，截止频率ｆｃ和高频线性部分的斜率Ｋ均随浸泡时间的延长而变化，在发生点蚀时三者均趋于极值，但三者都不能单独正确地表征点蚀的强度和趋势 实验结果同时表明；点蚀时．从不同材料的 ＳＰＤ曲线获得的点蚀参数 ＳＥ和 ＳＧ的数值具有一致性．且与未点蚀时的参数值存在着明显的区别 一般而言，点蚀发生时，ＳＥ＞５且 ＳＧ＜１；非点蚀时，二者的取值正好相反 ．因此，二者可以很好地表征点蚀的发生．更多还原

【Abstract】 Electrochemical noise(EN) test of aluminum alloys LC4, LY12 and pure aluminum in 2.0%(mass fraction) NaCl solution(pH=7.01) was reported. The potential fluctuation of the electrodes was recorded in time domain and simultaneously processed by fast Fourier transform method to gain spectra power dendsity(SPD) curves in frequency domain. It is found that EN characteristic varies with materials, that is, in time domain, pure aluminum and LC4 can stochastically exhibit sudden potential drop, which results in a sharp peak in potential-time curves, but LY12 does not. And the three features in SPD curve: W(white noise level), fc(cutoff frequency), and K(the slope of the high frequency domain), all change with the corrosion process and reach their extremum when pitting occurs. Any single parameter cannot correctly predict the strength and trend of pitting. However, two parameters SE and SG derived from the SPD curves can correctly predict whether pitting has occurred or not. That is, for different materials, pitting corrosion usually occurs when SE >5 and SG <1.更多还原